Error: titration takes too long

[Gurdjieff]

Hello

I recently bought and installed a KH Director in my aquarium. I have performed each of the directions of the manual successfully, but when I try to take a measurement the result is always the same: Error: titration takes too long.

The first location of the KH Director was in the back of the aquarium (in a control room) so the tube was more than 3 meters long, I thought that maybe that was the problem so I changed the KH Director to the cabinet, now the water sample tube is only 1.20 meters but the error still persists.

Calibration of the pumps (reagent and water sample) was successful, the PH probe was also calibrated, the equipment is leveled, connections are in place, firmware was updated...

So I wonder what the problem could be. Any ideas?

Thank you

Gonzalo